Multiplexing USB together from 2 devices

Other Hardware LEDs and Multiplexing
1

I'm using this hardware to multiplex 2 mouse's to the same PC at once:
http://www.circuitsathome.com/arduino_usb_host_shield_projects

It works like this with a browser:
https://www.google.com/intl/en/chrome/multitask.html

But my PC keeps rebooting. What am I doing wrong?

2

You can test drive what the interface feels like, just click on the blue button in the above Google link,
after you watch the video.